Manufacture of textile fibers composed of casein



Patented Apr. 10, 195i t COMPOSED or CASEIN Antonio- Ferretti,Milan-Italy N0 niawiii'g; Application December Se rialNoI 714,130;Inltaly Mirch'G, 1941' Section 1, PublicLaw sec, AiiEiist 'B, 1946-Patent expires Marc1i*-6, 1 96-I- 1; This invention relates to themanufacture of textile fibres composed of casein or" partly of caseinand partly of cellulose u It is known to treat azr'tificial fibrescomposed of cellulose (rayon) first with'a solution of urea and then,after thefib'r has" absorbed a sum- Ciiit dlialit itvo f urea; withformaldefii'ael s0 astofoiiii on the fibre an inl soluble l roduct'of'co'ndens'ati'oii' which parti'allj Waterproofs the fibf'andrehdis itmorefh ighly resistant the effects of moisture} and atthe saffx'ie'tiiiieto'obtairi a" fib'rewhich is crjeaseles'sl' Attempts'li'ave beenmadealso to" treat casein fibresifithe Sarfi way; that is firstwitli'ui'ea and then Withformaldehyde". Ithas'been'found', however; thatSlic'h' treatment fa'ilsto' p'io'dube anyappreciableefiect on thecasein'fibrei' This" is diie t'o'fthe fact that a casein fibre, that is,as

ordinarily ro'duced, with the use of formame hyde in the insolubilisingtreatment; contains for-f ni'aldehyde and for the reason ispreventedfrom' absorbing the necessary quantityo'f urea; which insteadof cominginto*co'ntact with-theform-' aldehydealre'a'dy present'in 'thefibres condenses on the exterior surface thereof and thereforms a''pulverulent deposit of condensed "urea "effective to prevent thepassage" of urea into'the' interior of the. fibrei V It is further knownthat; casein dissolves" in aqueous solutions" of] urea and it is knownalso to use a"solution'of casein in anaqueous'solu tion of urea asthespinningsolution in themanu;

facture 10f wet-spun fibres, that is, fibres-prof dupedby spinninga"solution of the basic substance of which the fib're is to 'be'composedin a coagulation bath operative to coagulate the thin stream ofsolutio'nentering the bath into a filament. Successful results are, however, not

obtainableby' this process: it 'isdifficult to obtainperfectcoagulation. In addition,"a spongy load tends to' form inside the fibli'durfingthestep of insolubilisingthe fibre with form aldehyde, This isdue to the morerapid rea tion of the formaldehyde with the 'urea" contained in-the fibre than witnthetasenr of; which the fibresis composed,the' urea; fibre hardening in consequence 'before the 'casiein substanceof the fibre and forming in "the resultan amorphous orspong'y loadinsidefthe' 'fib-re. Owing to thepresence of v thisfload in the fibre,

. the latter is'less resis'tanttodryness and'inoisture, According to thepresent"invention; a"processf composed of casein or partly or casein andpafift of? cellulose; comprisesspinning a solutionfmore especially anaque'oussqlutiong; of. casein or ..of

a; mixture .of' casein," and. cel1ulosic viscosein a:

formaldehyde-free, poagulation: bath, and .treat ing the1 coagulated-:filament; in a succession ,pfi baths including ,or comprising, inmthe,order.

named; (a) a bath-or baths consisting-10f urea dissolved. in a"solution, morev especially: an .aque-,. ous solution, of a neutral oracid salt of, azmineljal. or organic acid and; (b); ..a. urea wiressaline bath or: baths containing formaldehyde; moreespeciallyianiaqueous;batlror-bathsof thisdescriptiom; It; is" tobe}understood that the successiomof;

baths through which:the coagulated, iilament is passed-i1! :Qrfder toproducefi i hedfibre may ciudezother baths.- additional to ,the baths-(a); and: Kb) mentioned above. for. example: deacidiflying andpartially, hardening baths, as ingthe,

specific examples-of the invention hereinafter set forth.

The: baths or baths (dif or are and possessed of, an astringent actiontowards the"filament;Itorithey may I01, example, be

of a;.comDosition; -similar;touthe baths h t are. used in the processesforming the subjectmatter of U. S. patent applications .dated August.17,

April "4; 1939., SeraNoL 270,9 19, ,noyv .abandqngg i b u y 17, 19 .8,.senwNot v 30.12 1.J W ab ndoned;,Ju1y-:3 11940, fier- .N.o.. e18. 9..:no a n cloned; and U. S. Patents No. 2,338,915; No. 2,297,397; No.2,338,911,;

It is found that case fibres and mixed casein and. cellulose f'fibre'sproduced'in accordance with thj present'finven iras outlinedaboveare'cona sidjerably'improve as compared with casein fibres andmifieiicasein: cellulose fibres" as" ordi-' narily' prdducedf inf fres'pectof-resistanceitq mois= I ture, resistance td 'thej boiling acidbathsthat are used for dyeing andresistance to soap"and" water in theinaphine of fast "colors.

F t i ibiwm t zfr s est' o t dl r. going propertiesfantl a higheriorderof st'rength" with rynes and; moisture *o ffthe fibre are ob' .e, jrsafeea a nuo i thiea i t rs'mslfi least th a or baths containingiorma'ldehyd'orafter *the" fila' it is out, it being: convenient toitreat in this manner a large number o'f filaments simultane ou'slyspunfin the coagulating? bath ria-- then l j' t e l' h quent"(post-coagulatio proc ss ionni ath s b, H a plicationsfd'atedFbrUa'iyTY, 1938; SGT.

'aW'n' out and en-i" i es ates- 330,725 now abandoned; July 31, 1940,Ser. No. 348,992 now abandoned; and U. S. Patent No. 2,338,917.

In order to obtain a higher resistance of the fibres that are producedin accordance with this invention to acid boiling than is obtainablewith the use of normal temperature in the baths (a) and (b) atemperature above 28 C. may be employed in those baths or at least inthe bath or one or more of the baths (1)) containing formaldehyde, as inthe process forming the subject matter of the aforesaid U. S. patentapplications No. 330,725, 348,992, both now abandoned and U. S. PatentNo. 2,338,917, for example, if a temperature not above 25 C. has beenused in the bath or baths (a) and also in one or more of theinsolubilising, formaldehyde containing baths (1)), a temperature above25 C., preferably a temperature of 70-75 C., may be employed in anotheror other of the baths (2)) subsequent in the succession of baths to thefirst-mentioned of the baths (b). In this way, the fibre obtained willbe much softer and larger after acid boiling than a urea-free fibre andfrom. this point of view, can be compared with a fibre treated with achromium salt, but with the advantage, however, that the fibre retain aperfectly white appearance.

It should be remarked that casein filaments alreadycoagulated but notyet insolubilized by formaldehyde, cannot be treated with a simplesolution of urea, as a simple solution of urea dissolves casein and inconsequence the filament would at once dissolve in the solution. On theother hand, by using a saline solution of urea; preferably concentratedand astringent, no dissolving of the filament occurs, but only a slightswelling of the filament, which can be adjusted at will by varyin thedegree of concentration and/or the astringent capacity of the solutionaccording to the amount of urea that has to be absorbed by the filamentand to the degree of penetration of the urea that has to be obtained.

Urea may in some cases be present in the formaldehyde-free acid saltcoagulating bath, but in general, coagulation of the filament ishindered and there tends to be a large loss of urea in the firstde-acidifying bath following the coagulating bath.

Examples '1.- 100 kgs. of washed and dried casein are swelled in waterand then dissolved in an aqueous solution of caustic alkali, equivalent,for instance, to 20 litres of sodium hydrate at 5 B. The volume of theresulting solution of casein is then increased to 500 liters, afterwhich the solution is filtered one or more times. After maturation it isspun in theform of filaments in a formaldehyde-free coagulating bathcontaining, for instance, 90 gms. of 66 Baum sulphuricacid and 350 grs.of sodium sulphate per litre of the bath. The filaments emerging fromthe coagulating bath are gathered together in a continuous ribbon andpassed on, preferably under more or less tension through the followingbaths in succession:

(a) An aqueous saline bath containing 200 gms. of sodium. chloride perlitre.

(b) An aqueous saline bath containing 150 gms. of sodium chloride, 200gms. of aluminium sulphate and 150 gms. of alumina paste containing ofA1203 per litre.

(0) An aqueous saline bath having the composition of the bath (1)) butcontaining in addition gms. of urea crystals per litre of the bath andmore sodium chloride until the bath is saturated.

(d) An aqueous saline bath having the composition of the bath (b) butcontaining in addition 39-40 gms. of 100% formaldehyde per litre of thebath.

The fibres are now out to the required length after which they aretreated, preferably in an autoclave, in an aqueous bath (e) containinggms. of aluminium sulphate, 200 gms. of sodium chloride and 40 gms. of100% formaldehyde per litre, for 5-6 hours.

The insolubilized fibres are now washed and treated in an aqueous bathor baths (1) of soluble phosphates, for instance such a bath containing4 gms. of monosodium phosphate per litre, after which the fibres arewashed again and dried.

The preferred temperature for the various baths are: 35 l0 C. for bath(a) 50-55 C. for bath (b):

35-40 C. for bath (0):

50-55 C. for bath (d):

70-75 C. for bath (e):

35- l0 C. for bath or baths (7):

II. The procedure in this example is the same as in Example I, exceptthat the filaments are out after bath (0) instead of after bath ((1),the out fibres being gathered together in a vessel containing bath ((1),in which they are treated for 3-4 hours at 35-40 C., then treated inbath (e) at 70-75 C. for 5-7 hours, then washed, then treated in thebath or baths (1) and finally, washed again and dried.

III. The procedure in this example is the same again as in Example I,except that the filaments are out after the bath (b) instead of afterbath (d), the cut filaments being gathered together in a vesselcontaining bath (0) in which they are treated for 2-3 hours at 35-40 C.,and then, after having been squeezed out, in conformity with Example II,omitting bath (e).

IV. The procedure in this example is the same again as in Example I,except that the aluminium sulphate in bath (e) is replaced with moresodium chloride until the bath is saturated.

V. The procedure in this example is the same as in Example I to IV withthe use of the baths (a), (b), (c), (d), and (e) as specified therein,with the exception that the aluminium sulphate and/or sodium chlorideare either partly or totally substituted in the baths with other solubleneutral or acid salts including, for example, sulphates, chlorides,formiates, acetates, lectates or nitrates, of the mineral or organicacids.

It is to be understood that the term urea as employed herein includesall soluble salts containing urea such for example as thio-urea.

It is also to be understood that the invention includes both the use ofmilkcasein and also the use of vegetable casein for example soya beancasein, either being used alone or the two in admixture with oneanother.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is performed, I declare that whatI claim is:

1. Process for manufacturing casein textile fibers comprising the wetspinning of the casein solution into a coagulating bath free offormaldehyde to form casein filaments; and, after removal from saidbath, treating such filaments in at least one bath containing asubstantial con- .centration ofurea, but being free of "formaldee hyde,"whereby uncondensed urea penetrates the filaments and is absorbedtherein, said urea bath containing at least one non-basic soluble saltrendering the bath substantially saline and thereby functioning to adegree sufiicient for the protection of the filaments against dissolvinginto such bath; and thereafter removing such urea-containing filamentsfrom said urea bath and treating the same in at least one urea-freeformaldehyde bath of saline character for insolubilizing the same.

2. Process as in claim 1 and wherein the urea bath is rendered saline byincorporating therein to the saturation point non-basic soluble saltmaterial.

3. The process as in claim 1 and wherein the urea bath is maintained attemperatures elevated above 25 C.

4. The process as in claim 1 and wherein the urea bath is maintained atan elevated temperature of about 35 to 40.

5. Process as in claim 1 and wherein the coagulated filaments are keptunder stretching tension during passage through the coagulating and ureaand formaldehyde baths until the time when the hardened fibers are cutto length.

6. Process as in claim 1 and wherein the coagulated filaments are keptunder stretching tension during passage through the saline washing bathand the saline bath containing sodium chloride and an aluminum salt andthe saline bath containing urea and the saline bath containingformaldehyde.

7. Process as in claim 1 and wherein the aqueous urea bath is renderedsaline by the addition of sodium chloride and an aluminum salt.

8. Process as in claim 7 and wherein the aluminum salt is aluminumsulphate.

9. Process as in claim 1 and wherein the aqueous urea bath is renderedsaline by the addition of sodium chloride and aluminum sulphate.

16. Process as in claim 1 and wherein the aqueous urea bath is renderedsaline by the addition of sodium chloride and aluminum sulphate in theproportions, per liter, of about grams of urea crystals, about gramsinitially of sodium chloride, and about200 grams of aluminum sulphate;the sodium chloride content bein then increased unti]. substantialsaturation is reached.

11. Process as in claim 10 and wherein the aqueous urea bath is addedabout 50 grams of aluminum paste containing about 10 percent of aluminumoxide.

ANTONIO FERRETTI.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Meigs Aug. 20, 1940 deKadt Mar. 2, 1943FOREIGN PATENTS OTHER REFERENCES Ser. No. 327,734, diVascO (A. P. C.),published Apr. 27, 1943.

Number Number

1. PROCESS FOR MANUFACTURING CASEIN TEXTILE FIBERS COMPRISING THE WETSPINNING OF THE CASEIN SOLUTION INTO A COAGULATING BATH FREE OFFORMALDEHYDE TO FORM CASEIN FILAMENTS; AND, AFTER REMOVAL FROM SAIDBATH, TREATING SUCH FILAMENTS IN AT LEAST ONE BATH CONTAINING ASUBSTANTIAL CONCENTRATION OF UREA, BUT BEING FREE OF FORMALDEHYDE,WHEREBY UNCONDENSED UREA PENETRATES THE FILAMENTS AND IS ABSORBEDTHEREIN, SAID UREA BATH CONTAINING AT LEAST ONE NON-BASIC SOLUBLE SALTRENDERING THE BATH SUBSTANTIALLY SALINE AND THEREBY FUNCTIONING TO ADEGREE SUFFICIENT FOR THE PROTECTION OF THE FILAMENTS AGAINST DISSOLVINGINTO SUCH BATH; AND THEREAFTER REMOVING SUCH UREA-CONTAINING FILAMENTSFROM SAID UREA BATH AND TREATING THE SAME IN AT LEAST ONE UREA-FREECORMALDEHYDE BATH OF SALINE CHARACTER FOR INSOLUBILIZING THE SAME.